Compressor lubricating system



April 18, 1950 c. STEENSTRUP 2,504,748

COMPRESSOR LUBRICATING SYSTEM Original Filed June 20, 1944 Inventor: Christian Steenstr up,

His Attorney.

Patented Apr. 18, 1950 COMPRESSOR LUBRICATING SYSTEM Christian Steenstrnp, Schenectady, N.

Y., as-

signor to General Electric Company, a corporation of New York Original application June 20, 1944, Serial No.

541,145. Divided and this 1945, Serial No. 596,498

schim. l

My invention relates to compressors for refrigerating machines and the like and particularly to lubricating systems for such compressors. This application is a division of application Serial No. 541,145, tiled June 20, 1944, now Patent No. 2,- 394,409, and assigned to the same assignee as the present application.

Refrigerant compressors for household refrigerators are required to operate in locations where the noise level is low, and itis desirable to eliminate or minimize all noises produced by the normal operation of the compressor. In order to insure a minimum of wear and of noise it is desirable to provide an adequate supply of lubricant which preferably is maintained at some predetermined pressure throughout the operation of the compressor. Sudden changes in pressure, however, may produce noise in the lubricant supply system and it is desirable to regulate the pressure of the lubricant and prevent sudden changes in pressure. Accordingly it is an object of my invention to provide a compressor for refrigerating machines and the like -including an improved device for regulating the pressure of the lubricant and preventing sudden changes in pressure.

The details of my invention are set forth in the following description and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention reference may be had to the accompanying drawing in which Fig. 1 is a longitudinal side elevation, partly in section, of a hermetically sealed refrigerant compressor embodying my invention; Fig. 2 is an end view of the compressor shown in Fig. 1 with the casing cut away and with portions of the compressor shown in section; Fig. 3 is an enlarged View of the lubricant pressure regulator illustrated in Fig. 2; and Fig. 4 is a sectional view on line 4-4 of Fig. 1 showing the construction ofthe lubricant pump.

Referring now to Figs. 1 and 2, I have provided a hermetically sealed motor-driven refrigerant compressor unit I including a cylindrical shell 2 having end plates 3 and 4 welded or otherwise suitably bonded thereto to form an enclosing casing. The shell 2 is constructed preferably of steel and constitutes the frame in which is supported a laminated core structure 5 of an alternating current driving motor 6. The laminations 5 are held in place between annular rings 'l and 8 which are welded or otherwise suitably secured to the shell 2. The motor is provided with stator windings 9 which are energized through leads III passing through sealed fittings II to the exterior of the casing. A compressor I2 is arranged within the casing I and comprises a. cylinder application May 29,

2 block I3 which is rigidly secured to the ring. by suitable bolts or screws I4. The cylinder block I3 is provided with a cylinder I5 in which is located a piston I3. The piston is driven by a crank shaft I1 mounted in a bearing I 8 in the block I3, the motor 6 being provided with a squirrel cage rotor I9 mounted on the shaft I1. The shaft I1 is provided with annular shoulders 20 and 2l on either side of the crank and the end of the shaft remote from the motor I9 is mounted in a bearing block 22 which is sldable axially in a circular opening 23 in the cylinder block I3. The shoulders 20 and 2l are mounted in running engagement with annular thrust bearings 24 and 25, respectively, and are retained in position by a dished bridging member or disk 26 in cooperation with a movable camming member or adjusting plate 21. The compressor is provided with intake and exhaust valves (not shown) which are located within a cylinder head 28. Refrigerant gas which is admitted to the compressor through a pair of intakes 29 ows through an intake muiller 30 and thence into the compressor head through a conduit 3I. The gas cornpressed within the cylinder I5 by operation of the piston I6 is discharged through a connection 32 into an exhaust muffler 33 and ows from the exhaust muffler and out of the casing through a conduit 34 to the circuit of the refrigerating system (not shown). Vaporized refrigerant return-` ing from the refrigeratng system is admitted to the casing through a. suction line or return conduit 35.

In order to lubricate the compressor, a body of oil or lubricating huid is maintained in the casing I to a level indicated at 36. Lubricant is withdrawn from the sump through a Velocity reducing intake baille 31 and an intake passage 38 in the block I3 by operation of a pump 39 the details of which are shown in Fig. 4. The intake baille 31 prevents the admission to the pump .of gaseous or liquid refrigerant and also of particles of foreign matter which may collect in the bot tom of the casing. This intake baffle construction is the invention of Carl H. `Steenstrup and is described and claimed in application Serial No. 541,143, filed June 20, 1944, now Patent Number 2,485,417, and assigned to the same assignee as the present invention. The pump 39 comprises an eccentrically formed section of the shaft I1 and a spring-pressed vane 40 for separating the intake and exhaust sides of the pump. During the operation of the pump, lubricant is drawn in through the duct 38 and is discharged through a duct 4I formed as a groove in the walls of the shaft bearing. 'I'he oil enters an annular passage 42 about the shaft adjacent the thrust bearing 24 and ows through the passage 43 in the crank shaft to an annular groove 44 in the bearing block 22. From the groove 44 the oil ilows through a passage 45 in the block 22 to a passage 4l in the cylinder block Il, these two passages being maintained in registry by keying or otherwise securing the block 22 against rotation in the opening 28. The passage 48 conducts the oil to an oil pressure regulator 41 of the spring-pressed piston type. Oil discharged from the regulator 41 then ilows through a duct 55 to an annular groove 4I about the walls of the cylinder I5 to lubricate the piston I6. It is thus apparent that oil is supplied to all moving parts of the compressor assembly.

The motor compressor unit may be supported in any suitable manner on the structure with which it is to be employed and has been illustrated as resiliently suspended on springs 49 and 5l at either end thereof. During the operation of the compressor, lubricant which is supplied to all the moving parts thereof reduces noise and wear. However, sudden changes in lubricant pressure such as might be caused by movement of the regulator piston 41a to control the ilow of lubricant through the exhaust port indicated at 54 may tend to produce objectionable noise and it is therefore desirable to prevent sudden changes in pressure of the oil throughout the operation of the compressor. The pressure regulator 41 is provided for this purpose. The details of the regulator are more clearly shown in Fig. 3 in'V which the regulator piston designated 41a is shown mounted in a cylinder 5I and pressed toward the left by a spring 52 which is compressed between the piston 41a and a disk 53 secured in the open end of the cylinder 5i. The pressure of the oil entering the cylinder 5| through the passage 45 tends to move the piston 41a` to the right in opposition to the force exerted by the spring 52. The intake port for the cylinder 5I is the upper end of the passage 46. The exhaust port oi the cylinder at the lower end of the duct 55 is indicated at 54 and communicates with the 1. In a compressor or the like having a pump for supplying liquid lubricant and a conduit for conveying the lubricant to the moving parts of the compressor, a lubricant ilow regulating means including a spring-pressed piston arranged to control the flow of lubricant through the conduit, said regulating means including a bypass around said piston for affording a predetermined minimum now of lubricant through the conduit to the moving parts of the compressor regardless oi' the position of said piston with respect to the conduit whereby noise produced by the sudden closing of the conduit is minimized.

2. In a compressor or the like having a pump for supplying liquid lubricant, means providing a conduit for conveying the lubricant to the moving parts of the compressor, said means including a cylinder having an inlet port at one end and an outlet port at one side and connected to form a portion of said conduit, a piston and a spring for urgingI said piston toward said end of said cylinder for controlling said outlet port in accordance with the pressure of the lubricant supplied annular passage 48 through the duct 55. During the operation of the refrigerating machine, the piston 41a moves back and forth across the exhaust port 54 depending on the pressure of the oil entering the cylinder 5I through the passage 45, and if the cutofi' is sharp sc that the flow of the stream of oil is suddenly started or stopped,

, said piston providing communication between said recess and said end of said cylinder.

3. In a compressor or the like having a pump Y for supplying liquid lubricant and means pronoise is produced. In order to minimize the i noise due to sharp cutoil, there is provided a bypass between the intake or upper end of the duct 45 and the exhaust port 54 which comprises an annular groove arranged about the end of the piston 41a and communicating with the end oi' the cylinder 5I adjacent the intake port through a groove 51 formed in one side and across the top of the piston. The spring 52 is mounted between the piston and the stationary disk 53, and the piston 41a may rotate within the cylinder 5|; however, since the groove 55 extends entirely about the piston, the bypass is maintained open between the inlet and exhaust ports o! the cylinder 5l regardless of the position of the piston. Because there is always a ilow of lubricant through the bypass during the operation of the mechanism, sharp cutoff is prevented and the noise is minimized. A damping action for the piston 41a is obtained by providing a small restricted opening 58 in the disk 53 to provide communication between the cylinder 5l and the interior of the casing 2 about the cylinder block I3. Oil or a mixture of oil and gas will lill the cylinder 5I back of the piston 41a,

viding a conduit for conveying the lubricant to the moving parts of the compressor, said means including a cylinder, a lubricant flow regulating means including a spring-pressed piston arranged to control the flow of lubricant through the conduit, said regulating means including a bypass around said piston for affording a predetermined minimum ilow of lubricant regardless of the position of said piston with respect to the conduit whereby noise produced by the sudden closing of the conduit is minimized, and a cover for said cylinder for enclosing said piston therein and for providing a chamber at the rear of said piston adapted to be lled with fluid, said cover having a restricted opening therein whereby the iluid in said chamber damps movement of said piston.

CHRISTIAN STEENSTRUP.

REFERENCES CITED The following references are of record in the 7o ille of this patent:

' UNITED sra'ras PATENTS 

